Metformin Hydrochloride (Metformin HCl) is a biguanide antidiabetic active pharmaceutical ingredient (API) widely used for improving glycemic control in patients with type 2 diabetes mellitus. It is commonly used as an oral antidiabetic medicine and may be formulated as immediate-release or prolonged-release pharmaceutical products.
Metformin primarily reduces hepatic glucose production, decreases intestinal glucose absorption, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization. Unlike sulfonylureas, metformin does not ordinarily stimulate insulin secretion or cause hyperinsulinemia.
Metformin HCl is an established diabetes and endocrine pharmaceutical API used in the manufacture of oral pharmaceutical formulations. It is available as a white or almost white crystalline substance and is freely soluble in water.
Metformin HCl API quality control focuses on assay, identification, related substances, loss on drying, sulfated ash, impurity profile and other applicable pharmaceutical quality parameters.
CAS Number: 1115-70-4
Molecular Formula: C₄H₁₂ClN₅
Molecular Weight: 165.62 g/mol
Chemical Name: 1,1-Dimethylbiguanide hydrochloride
Synonyms: Metformin Hydrochloride, Metformin HCl, 1,1-Dimethylbiguanide Monohydrochloride
Drug Class: Biguanide
Therapeutic Class: Antidiabetic Agent
Therapeutic Area: Diabetes / Endocrinology
Molecule Type: Synthetic Small Molecule
The BP 2025 monograph identifies Metformin Hydrochloride as 1,1-dimethylbiguanide hydrochloride, with CAS 1115-70-4 and molecular mass approximately 165.6.
Metformin improves glucose tolerance by acting on several components of glucose metabolism. It:
Metformin HCl API is used in pharmaceutical formulations for:
The BP monograph lists preparations including Metformin Oral Solution, Metformin Tablets, Metformin Prolonged-release Tablets, Metformin/Sitagliptin Tablets and Metformin/Sitagliptin Prolonged-release Tablets.
Metformin HCl is commonly formulated as:
Current U.S. labeling includes 500 mg, 850 mg and 1000 mg immediate-release tablet strengths.
Metformin Hydrochloride is described as white or almost white crystals. It is freely soluble in water, slightly soluble in ethanol (96%), and practically insoluble in acetone and methylene chloride.
Melting Point: 222–226 °C
pKa: 12.4
pH of 1% aqueous solution: 6.68
Solubility: Freely soluble in water; slightly soluble in ethanol; practically insoluble in acetone and methylene chloride.
A controlled Metformin HCl API manufacturing process may include:
Metformin HCl API can be evaluated using:
The BP 2025 monograph specifies chromatographic controls for impurities including cyanoguanidine (Impurity A) and dimethylamine (Impurity F).
Store Metformin HCl API in well-closed containers at controlled room-temperature pharmaceutical storage conditions, protected from excessive moisture and contamination. USP information specifies preservation in well-closed containers and storage at room temperature.
Metformin HCl is a prescription antidiabetic medicine. Current labeling indicates use as an adjunct to diet and exercise for glycemic control in adults and pediatric patients 10 years and older with type 2 diabetes mellitus.
Metformin-associated lactic acidosis is a serious but rare adverse reaction, with increased risk associated with factors such as significant renal impairment, hypoxic states and certain other clinical conditions.
| Parameter | Specification |
|---|---|
| Appearance | White crystalline powder or crystals |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.1% |
| pH (1% Solution) | 6.68 |
| Individual Impurity | NMT 0.1% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 0.5% |
| Melting Point | 222–226 °C |